CHRONIC LARVAL CROWDING

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Context: Scientists from the Jawaharlal Nehru Advanced Centre for Research (JNCASR) have found that populations of insects that experience chronic larval crowding all evolve to give rise to larger and faster hatching eggs, even though they vary in other adaptations.

Key findings of study:

• Till around 2003, it was believed that fruit flies that adapted to larval crowding evolved greater competitive ability, invariably through evolution of a combination of higher larval feeding rate and greater pre-adult tolerance to toxic levels of metabolic waste products like ammonia and urea.
• In a paradigm shift of this understanding, researchers has revealed that the kind of traits that evolved depended not just on overall larval density, but rather on the specific combination of food amount and egg number at which chronic crowding was experienced.
• One particular adaptation, larger and faster hatching eggs is common for all fruit fly populations exposed to crowding, irrespective of their exposure to different combinations of food amount and egg number.
• For this study, the scientists used unique populations developed by the researchers through selection in the laboratory.
• This study has led to a paradigm shift in the understanding of density-dependent selection and adaptation to crowding in fruit flies.

https://timesofindia.indiatimes.com/india/chronic-larval-crowding-in-fruit-flies-steers-evolution-towards-larger-faster-hatching-eggs-jncasr/articleshow/91177397.cms